Flux and composition of interstellar dust at Saturn from Cassini's Cosmic Dust Analyzer
Flux and composition of interstellar dust at Saturn from Cassini's Cosmic Dust Analyzer
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DOI：
10.1126/science.aac6397
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发表时间：
2016-04-15
期刊：
影响因子：
56.9
通讯作者：
Gruen, E.
中科院分区：
文献类型：
--
作者：
Altobelli, N.;Postberg, F.;Gruen, E.
星际尘埃（ISD）是星际介质的凝聚态。卡西尼号宇宙飞船上的宇宙尘埃分析仪的现场数据显示，土星系统被来自我们邻近的星际邻居（即当地星际云）的 ISD 颗粒经过。我们确定了 36 个星际颗粒的质量分布、它们的元素组成以及土星 ISD 通量的下限。质谱和颗粒动力学表明存在富含镁的硅酸盐和氧化物颗粒，部分含有铁夹杂物。主要造岩元素（镁、硅、铁和钙）的含量在宇宙中含量丰富，颗粒间差异很小，但硫和碳却被耗尽。太阳附近的 ISD 颗粒似乎是均质化的，可能是通过在星际介质中的重复处理而实现的。
Interstellar dust (ISD) is the condensed phase of the interstellar medium. In situ data from the Cosmic Dust Analyzer on board the Cassini spacecraft reveal that the Saturnian system is passed by ISD grains from our immediate interstellar neighborhood, the local interstellar cloud. We determine the mass distribution of 36 interstellar grains, their elemental composition, and a lower limit for the ISD flux at Saturn. Mass spectra and grain dynamics suggest the presence of magnesium-rich grains of silicate and oxide composition, partly with iron inclusions. Major rock-forming elements (magnesium, silicon, iron, and calcium) are present in cosmic abundances, with only small grain-to-grain variations, but sulfur and carbon are depleted. The ISD grains in the solar neighborhood appear to be homogenized, likely by repeated processing in the interstellar medium.